The Juliancalendar was in general use in Europe from the times of the Roman Empire until 1582, when Pope Gregory XIII promulgated the Gregorian Calendar, which was soon adopted by most Catholic countries.

Russia remained on the Juliancalendar until after the Russian Revolution (which is thus called the 'October Revolution' but occurred in November according to the Gregorian calendar), in 1917, while Greece continued to use it until 1923.

A revised Juliancalendar was proposed during a synod in Constantinople in May of 1923, consisting of a solar part which was and will be identical to the Gregorian calendar until the year 2800, and a lunar part which calculated Easter astronomically at Jerusalem.

The Julian Day (JD) or Julian Day Number is the time that has elapsed since noon January 1, 4713 BC[?] (according to the prolepticJuliancalendar; or November 24, 4714 BC according to the proleptic Gregorian calendar), expressed in days and fractions of a day.

This "Julian" in "prolepticJuliancalendar" and "Julian year" refers to Julius Caesar, who introduced the Juliancalendar in 46 BC.

Julian dates are typically used by astronomers to calculate astronomical events, and eliminate the complications resulting from using standard calendar periods.

This is in contrast to the Gregorian calendar, which is based solely upon a solar cycle, or the Islamic calendar, which is purely lunar.

Jews use this calendar to determine when the new Hebrew months start; this calendar determines the Jewish holidays, which Torah portions to read, and which set of Psalms should be read each day.

The epoch of the modern Hebrew calendar is Monday, October 7, 3761 BCE, being the tabular date (same daylight period) in the prolepticJuliancalendar corresponding to 1 Tishri AM 1 (AM = Anno Mundi = in the year of the world).

Julian dates may be applied both before the calendar was invented (proleptic) and after it was replaced as long as it is clear that the Julian leap year rules are being applied.

The Julian Day Number or JD of a particular instant of time is the number of days and fractions of a day since 12 hours Universal Time (Greenwich mean noon) on January 1, -4712, in the Julianprolepticcalendar.

The Hebrew calendar is the official calendar of Israel and it is the liturgical calendar of the Jewish faith.

www.geocities.com /atkuala/astro/cal_conversion.html (423 words)

Learn more about Proleptic Julian calendar in the online encyclopedia.(Site not responding. Last check: 2007-11-03)

The prolepticJuliancalendar is produced by extending the Juliancalendar to dates preceding its official introduction in 45 BC.

This is the convention used in the "astronomical Juliancalendar".

Because the JulianCalendar was actually used before that time, one must explicitly state that a given date is in the Proleptic Gregorian Calendar when that is used.

The Juliancalendar was in general use Europe from the times of the Roman Empire until 1582 when Pope Gregory XIII promulgated the Gregorian Calendar which was soon adopted by most countries.

Russia remained on the Juliancalendar until the Russian Revolution (which is thus called the 'October but occurred in November according to the calendar).

Easter Pentecost and their associated holy days are calculated according to the Juliancalendar in Eastern Orthodox churches and some Eastern Orthodox continue to use the JulianCalendar for their church calendar dates.

The JulianCalendar remained in use into the 20th century in some countries, particularly in eastern Europe, and is still used by the majority of Orthodox faithful for ecclesiastical dates.

The Juliancalendar was in general use in western Europe from the times of the Roman Empire until 1582, when Pope Gregory XIII promulgated the Gregorian Calendar, which was soon adopted by most Roman Catholic countries.

A Revised JulianCalendar was proposed during a synod in Constantinople in May of 1923, consisting of a solar part which was and will be identical to the Gregorian calendar until the year 2800, and a lunar part that calculated Pascha astronomically at Jerusalem.

The difference of the length of the Juliancalendar year from the length of the real solar year is thus 0.0078 days (11.23 minutes) in the former case and 0.0076 days (10.94 minutes) in the latter case.

In fact a non-Gregorian calendar reform (involving a 33-year cycle and a prime meridian running through Virginia) would have stabilized the vernal equinox at March 21 for the whole world, but this possibility (assuming it was considered by the Pope) was rejected, presumably on political grounds.

The Gregorian Calendar was adopted immediately upon the promulgation of Pope Gregory's decree in the Catholic countries of Italy, Spain, Portugal and Poland, and shortly thereafter in France and Luxembourg.

In the 16th century the Gregorian Calendar Reform was introduced to improve its accuracy with respect to the time of vernal equinox, but the changes are relatively minor.

Russia, remained on the Juliancalendar until after the Russian Revolution (which is thus called the 'October Revolution' but occurred in November according to the Gregorian calendar).

Easter, Christmas and New Year are still calculated according to the Juliancalendar in the Eastern Orthodox churches, and some Eastern Orthodox churches continue to use the JulianCalendar for all their church calendar dates.

The "leap-year calculation" rule: In the Juliancalendar, there is a simple rule that says that every year that is divisible by four is a leap year.

However, in our familiar Gregorian calendar, the rule is slightly more complex: Every year that is divisible by four is a leap year, except that every year that is (a) divisible by 100 and (b) indivisible by 400, is not a leap year.

Occasionally you'll see proleptic anniversaries (for example the anniversary of the October Revolution is in November), but non-prolepticism is the norm (for example Columbus's discovery of America was on October 12 1492 Julian and the first official celebration of the event was on October 12 1892 Gregorian).

The Juliancalendar was in general use in Europe from the times of the RomanEmpire until 1582, when Pope Gregory XIII promulgated the GregorianCalendar, which was soon adopted by most Catholic countries.

Russia remained on the Juliancalendar until after the Russian Revolution (which is thus called the 'October Revolution' butoccurred in November according to the Gregorian calendar).

A Revised Juliancalendar was proposed during a synod inConstantinople in May of 1923,consisting of a solar part which was and will be identical to the Gregorian calendar until the year 2800, and a lunar part whichcalculated Easter astronomically at Jerusalem.

The Julian day number associated with the solar day is the number assigned to a day in a continuous count of days beginning with the Julian day number 0 assigned to the day starting at Greenwich mean noon on 1 January 4713 BC, Julianprolepticcalendar -4712.

The National Calendar of India was last reformed in 1957: Its leap years coincide with those of the Gregorian calendar, but years begin at the vernal equinox and are counted from the Saka Era (the spring equinox of 79 CE).

A solar calendar should be engineered to make the long-term ratio of the number of days to the number of elapsed calendar years (365.2425 for the Gregorian calendar) as close as possible to the observed number of days in a tropical year, which is slightly less than 365.2422.

One unpleasant feature about the Julian date, however, is that it counts dates from noon (so if we wish to designate a day by the integral part of the Julian date, it will change at noon), whereas nearly all calendars either change day at sunrise, or sunset, or midnight, but certainly not at noon.

The year 2000 of the Gregorian lunar calendar (golden number 6, epact 24; this year is embolismic) starts on 1999-12-08 of the Gregorian solar calendar, which is the day which starts on Julian date 2451520.5.

The Mayan calendar is actually the conjunction of three or four independent (but related) calendars: the Haab and the Tzolkin, which together form the Short Count, the Long Count, and possibly the Lords of the Night, which we now describe in turn.

The Julian day number system is sometimes (erroneously) said to have been invented by Joseph Justus Scaliger (born 1540-08-05 JC in Agen, France, died 1609-01-21 JC in Leiden, Holland), who during his life immersed himself in Greek, Latin, Persian and Jewish literature, and who was one of the founders of the science of chronology.

At some point students of calendrical science decided that the Julian day number system would be very useful in their field, provided the notion of a "day", i.e., "nychthemeron", were changed to accord with that notion as commonly used in connection with calendars.

To use the term "Julian date" to mean day-of-year when the term also means a date in the JulianCalendar (not to mention its use in the third sense by astronomers and calendricists) is simply to invite confusion.

Julian Day Numbers, or the Julian Date (JD), is the absolute count of days that have elapsed since Noon 1 January 4713 BC on the JulianCalendar, or on what may more strictly be called the Julian"Proleptic"Calendar, meaning the JulianCalendar as applied to an era prior to its actual use.

Second, if we are using the Gregorian Calendar, a correction must be added to reduce the date on the Juliancalendar to that on the Gregorian.

Perhaps the most famous (relatively speaking) example is the prolepticJuliancalendar, which Judeo-Christian scholars have used to pin exact dates on Biblical and Talmudic accounts of past events.

Enacted by Julius Caesar (hence the name), the Juliancalendar became Roman law in 45 B.C. So any events occurring before 45 B.C. would be part of the prolepticJuliancalendar.

Using the prolepticJuliancalendar, the current Kali Yuga age began at midnight, Feb. 18, 3102 B.C. Of course, Hinduism preaches a continuous cycle of death and rebirth, so pinning down a Hindu "creation date" for the universe is beyond the context of the faith.